A method for reducing memory latency in a multi-node architecture. In one embodiment, a speculative read request is issued to a home node before results of a cache coherence protocol are determined. The home node initiates a read to memory to complete the speculative read request. Results of a cache coherence protocol may be determined by a coherence agent to resolve cache coherency after the speculative read request is issued.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method for reducing memory latency in a multi-node architecture, comprising: receiving a speculative memory read request from a coherence agent at a home node before results of a cache coherence protocol are determined; initiating a read to memory at the home node to complete the speculative memory read request before results of the cache coherence protocol are received by the home node; and issuing a confirm or cancel command to the home node based upon the results of the cache coherence protocol.
2. The method of claim 1 , further comprising: buffering results of the read to memory.
3. The method of claim 2 , further comprising: dropping the results of the read to memory on a buffer full condition or if a cancel command is received.
4. The method of claim 3 , further comprising: if a confirm command is received after results of the read to memory are dropped, initiating a second read to memory to complete a memory read request.
5. The method of claim 4 , further comprising: forwarding results of the second read to memory to a requesting node.
6. The method of claim 3 , further comprising: if a confirm command is received before results of the speculative read are dropped, forwarding the results of the read to memory to a requester.
7. The method of claim 6 , wherein the speculative memory read request is issued by the requesting node.
8. The method of claim 6 , further comprising: receiving the results of the read to memory at the coherence agent; and forwarding the results of the read to memory to the requesting node.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
April 30, 2007
August 9, 2011
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